Abstracts

Pollination
and seed dispersal determine the spatial pattern of gene flow in plant
populations, and for those species relying on pollinators and frugivores
as dispersal vectors animal activity plays a key role in determining this
spatial pattern. For these plant species, reported dispersal patterns are
dominated by short distance movements with a non-negligible amount of immigration.
However, the contribution of seed and pollen to the overall contemporary
gene immigration is still poorly documented for most of plant populations.
In this study we investigated pollination and seed dispersal at two spatial
scales in a local population of Prunus mahaleb (L.), a species pollinated
by insects and dispersed by frugivorous vertebrates. First, we dissected
the relative contribution of pollen and seed dispersal to gene immigration
from other parts of the metapopulation. We found high levels of gene immigration
(18.50%), due to frequent long distance seed dispersal events. Secondly,
we assessed the distance and directionality for pollen and seed dispersal
events within the local population. Pollen and seed movement patterns were
non-random and with skewed distance distributions: pollen tended moved
up to 548 m along a close to N-S direction, and seeds were dispersed up
to 990 m frequently along the SW and SE axes. Animal-mediated dispersal
contributed a substantial amount of gene immigration into the local population
and had a markedly non-random pattern within the local population. Our
data suggest that animals can impose distinct spatial signatures in contemporary
gene flow, with the potential to induce significant genetic structure at
local scales.